. The major function of this Core (RRC-C) is to support the research of the two intervention studies in this OAIC, as well as that of pilot studies supported by the OAIC. A second important function of RRC-C is to train young investigators in geriatrics and gerontology who are interested in research relevant to maintenance of functional independence of the elderly, in the performance of the procedures available within the RRC- C. To the extent that the investigators' time and the resources of the RRC-C permit, the RRC-C will also support other pilot and preliminary studies as well as funded studies in geriatrics and gerontology. Use of this Core will be prioritized on the basis of the relevance of the research to the goal of this OAIC, which is to find effective means of preventing and reversing physical frailty and maintaining functional independence of the elderly. The specific functions of RRC-C are: a) to perform the graded exercise stress tests; b) to measure the maximal attainable rate of oxygen uptake (VO2max); c) to assess cardiac output and total peripheral resistance by the noninvasive acetylene rebreathing method; d) to evaluate arterial stiffness by measuring pulse wave velocity; e) to evaluate left ventricular contractile function and diastolic filling dynamics using 2D echocardiography and Doppler ultrasound; f) to measure baseline blood pressure by auscultation and, in subjects with mild hypertension, by 12-hour ambulatory blood pressure monitoring; g) to train young investigators in geriatrics and gerontology who are interested in research relevant to maintenance of functional independence of the elderly, in the performance of the above procedures; h) to make the facilities and equipment of RRC-C available to young investigators in geriatrics and gerontology doing research relevant to maintenance of functional independence of the elderly i) to the extent that the time and support available in RRC-C permit, to provide assistance to other investigators in the performance of cardiovascular research relevant to prevention and reversal of physical frailty and maintenance of functional independence in the elderly. Performing these procedures in RRC-C instead of in each of the intervention and pilot studies increases efficiency by eliminating the need to have personnel trained in the performance of the procedures in each of the studies, and by eliminating the need to duplicate equipment. Furthermore, having all the procedures performed by the same team will enhance data quality by decreasing data variability.